亚热带植物水力性状与木质部解剖结构的关系

Relationship between hydraulic properties and xylem anatomical structure of subtropical plants

【目的】植物水力系统需要对不断变化的水分环境做出适应性调整,因此,量化植物水力性状与木质部解剖结构在不同水分状况下的关系,将有助于理解植物的适应策略。【方法】以亚热带7种裸子植物和7种被子植物为研究材料,对比分析不同生境中(自然生境和人工生境)植物的栓塞抗性(植物导水率损失50%的水势)、输水效率和解剖结构的性状差异,探究植物水力性状与木质部解剖结构的关系。【结果】①在不同生境下,自然生境植物的输水效率(K_(s))较大,栓塞抗性(P_(50))较小,且植物解剖结构性状对不同生境植物水力性状具有一定指示性。②相关性分析表明:被子植物的导管水力直径、导管密度与K_(s)、P_(50)呈显著相关(P<0.05),但相关性在不同生境下呈相反趋势;裸子植物的管胞水力直径、管胞密度与K_(s)、P_(50)之间的相关性在不同生境中具有相同趋势。【结论】在湿润区内,植物通过增加输水效率以适应相对干旱环境的生存策略可能较为普遍。木质部结构与功能的差异可能是同一生境下植物水分策略存在差异的原因。

[Objective]Plant hydraulic system needs to adapt to the changing water environment.This study aims to quantify the relationship between plant hydraulic properties and xylem anatomical structure in different habitats,so as to understand the adaptation strategies of plants to water changes.[Method]Taking 7 species of gymnosperms and 7 species of angiosperms in subtropical zone as research materials,the differences of embolic resistance(water potential with 50%loss of plant hydraulic conductivity,P_(50)),water transport efficiency(K_(s))and anatomical structure of plants in different habitats(natural habitat and artificial habitat)were compared and analyzed,and the relationship between plant hydraulic properties and xylem anatomical structure was explored.[Result](1)In different habitats,K_(s) of plants in natural habitat was larger,and P_(50) was smaller.The plant anatomical structure traits had a certain indication of plant hydraulic traits in different habitats.(2)Correlation analysis showed that the conduit hydraulic diameter and conduit density of angiosperms were significantly correlated with K_(s) and P_(50)(P<0.05),but the correlations showed the opposite trends in different habitats.The correlation of tracheid hydraulic diameter and tracheid density of gymnosperms with K_(s) and P_(50) showed the same trend in both habitats.[Conclusion]It may be common for plants to adapt to relatively arid environment by increasing water transport efficiency in humid areas.The differences in xylem structure and function may be the reason for the differences in plant water strategies in the same habitat.